/* RESET & BASE STYLES */
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: Arial, sans-serif;
      background: #f5f5f5;
      color: #333;
      padding: 20px;
    }
    header, footer {
      background: #fff;
      text-align: center;
      padding: 15px;
      margin-bottom: 20px;
      box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    }
    .container {
      max-width: 850px;
      margin: 0 auto;
      background: #fff;
      padding: 20px 30px;
      border-radius: 8px;
      box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    }
    h1, h2 {
      text-align: center;
      margin-bottom: 20px;
    }
    .controls {
      text-align: center;
      margin-bottom: 20px;
    }
    .controls button {
      padding: 10px 20px;
      margin: 5px;
      font-size: 1rem;
      background: #007BFF;
      color: #fff;
      border: none;
      border-radius: 4px;
      cursor: pointer;
      transition: background 0.3s;
    }
    .controls button:hover {
      background: #0056b3;
    }
    canvas {
      display: block;
      margin: 0 auto;
      background: #e9f2f9;
      border: 2px solid #333;
    }
    .export-controls {
      text-align: center;
      margin-top: 15px;
    }
    .export-controls button {
      padding: 7px 15px;
      margin: 5px;
      font-size: 1rem;
      background: #28a745;
      color: #fff;
      border: none;
      border-radius: 4px;
      cursor: pointer;
      transition: background 0.3s;
    }
    .export-controls button:hover {
      background: #218838;
    }
    #message {
      text-align: center;
      margin-top: 10px;
      font-size: 1.2rem;
      color: green;
    }
